Yes Audyssey set them pretty much the same. Audyssey actually set the center 2db lower then left and right. It would be nice if someone else with Denon X4300 could check for the same.
I have been very happy with the HTM's. If you don't mind me asking what speakers are you running?
I am looking at amps on ebay all the time. Do you think these speakers will sound better from higher powered amp at moderate or close to reference levels?
I use Gedlee Abbey's which are a 12" waveguide design from Earl Geddes. They are conceptually similar using B&C DE250's (which the HTM's use a Chinese made improved clone) and 12TBX100. The HTM's use an eminence driver which isn't as expensive or have as fancy design features, but in practice its an amazing driver. It has very smooth response and very low distortion. The biggest advantage of the B&C 12 that mine use is a lot more power handling and xmax, but neither speaker has much bass so this isn't of practical importance. The power handling might be, but your speaker could handle over 500 watts and while mine can technically handle over 1000, at that point the crossovers become a weak link. Again, not of great practical importance. The HTM uses the SEOS waveguide which intentionally took advantage of Earl Geddes work to optimize its design, and arguably improve upon it. Hence why I consider the HTM to be a spiritual cousin. We aren't just talking about a 12" waveguide two-way with similar drivers, the waveguides themselves are similar.
At moderate volume when a solid-state amplifier is not clipping, you won't hear much difference if any at all. It's really at high volumes when the speakers are drawing enough power to clip. This is where the more powerful amplifiers will make a difference. While these speakers are very efficient, you can still find in many rooms where getting up at or slightly above reference will clip the amplifiers. My center channel was running on my 100+ watt receiver, my speakers are 96db's at 1 watt 1 meter, and I was clipping my receiver below reference levels while running them full range. Adding a high pass filter prevented this until much more uncomfortable levels, but it was still clipping during some dynamic peaks. This isn't surprising actually. Plug my 96db efficiency and 12 foot listening distance into a peak SPL calculator and it comes up with 104.7db's. That means I barely met the criteria for reference levels under that scenario. The calculator is imperfect and most receivers won't deliver their rated power during dynamic peaks because other speakers (In my case the 4 surround speakers) are also drawing from the receiver. This all explains why I was able to clip the amp.
Be creative when looking up amps, you might find better values. It needs to be 2-4 times more powerful than your receiver. A 200 watt per channel or 400 watt per channel amplifier would be good. Each doubling will give you just 3db's more headroom/output. Beyond that, remember that as long as we are dealing with a minimum quality of amplifier here that isn't too old, they won't sound much different. A mid 90's or early 2000's Parasound, Adcom, Anthem, etc. will all work great. A recent Emotiva, an ATI or any amp made by ATI, etc.
